Incandescent lamp



F. C. MCELROY INCANDESCENT LAMP Filed Nov. 4, 1925 llnl Nw iii Patented Nov. 27, 1%28.

UNW ens FRANK C. MCELBOY, OF COLUMBUS, OHIlO.

mcannnsonn'r LAMP.

Application filed November 4, 1925. Serial No. sa s'z This invention relates'to improvements in incandescent lamps, and is especially'directed' to lamps of the type adapted for use in con nection with the electrical illuminatlng systems of motor vehicles. The principal ob-' ject of the invention is to provide a lamp for the use specified wherein the lamp is formed to include a glass bulb. having a coating ap-' plied thereto of a translucent or opaque character and which is so disposed upon the bulb as to eliminateglare and other obnoxious light rays from a motor vehicle head light in which the lamp is operatively mounted.

Among other objects of the invention are: The provision'of' a lamp of the character stated which, when employed in a standard vehicle head light,.dispels light rays produced by the upper half of the parabolic reflector of the head light, this being accomplished primarily by arranging the translucent or opaque coating on the upper half of the lamp bulb; in further arranging said coating on the bulb to dispel the light rays produced by the center of the reflector around the axially positioned lamp socket; in extending said coating at the front of the bulb to conceal the light source therein; and in providing the neck of the bulb, where the latter is united with the base of the bulb with said coating so. that the light refracting irregularities appearing in this portion of the bulb will be covered and protected by said coating to avoid the production of uncontrolled or vagrant rays.

For a further understanding of the invention reference is to be had to the following description and the accompanying drawings, wherein:

Figure 1 is a side elevation of a lamp bulb formed in accordance with the present invention',

Figure 2 is a front elevation thereof,

Figure 3 is a vertical longitudinal sectional view taken through the bulb,

Figure 4 is a transverse sectional view on the line 4-4 of Figure 3.

Referring more particularly to the drawings the numeral 1 designates in its entirety the improved incandescent lamp comprising thepresent invention; As stated, this-lamp is intended primarily for use in connection with the illuminating systems of motor vehicles, although it will be appreciated that the invention is not limited in its scope to this particular use, but may be emp oyed wherever it may be found useful in controlling light production or in shielding the eyes of those around the same.

The lamp consists essentially of the usual co glass bulb 2, preferably formed from a clear transparent glass. This bulb is connected in the ordinary manner with the metallic base 3 of the lamp which is adapted to be mounted in connection with a suitable supporting t5 socket, in this instance the axial sleeve 4 of a parabolic head light reflector 5. I

In accordance with the resent invention the bulb 2 is provided wit a coating of a material possessing properties other than 7" transparency which may possess any degree oftrunslucency varying from a semi-translucent to a fully opaque character. Thus the coating may be in the form of a frosting which may be either white or'tinted to assume any desired color. The coating is usually applied to the exterior ofthe bulb, as shown in Figure 3, and extends over substantially onehalf the full area of said bulb in order that the upper half of the bulb will be completely coated to provide a main body portion.6 which is so arranged as to screen, ameliorate or in certain instances eliminate the casting of light from the light source 7 within the bulb upon the upper half of the reflector 5. WE

Substantially the lower half of the bulb 2 is fully transparent as indicated by the area 8, in order that light may pass in the usual manner from the filament 7 upon the lower half of the reflector 5 for projection from the vehicle head light. v .Assuming that the li ht source 7 occupies a focal center of the re ector 5 an arrangement is present which results in the production of a very eficient driving light but which is characterized by a total absence of such rays that produce glare in the eyes of approaching observers.

To further secure this desired end, the

front of the bulb has the coating extended as at 9 to lie below the main body portion 6 of Tim the coating. This lower extended area, as indicated at 9, completely conceals the light source 7 from a front view, so that said light source will be invisible to oncoming drivers.

In the manufacture of lam s of this char- 1% of irregularv or roughened form as indicated at 11 in Figure 3. This may be due to the cooling or chilling of the glass while the latter during process of manufacture is united with the base of the lamp. These irregularities result in the refraction of light rays passing therethrough, so that the refracted ray is issued from the lamp in vagrant uncontrolled paths. The present invention contemplates the extending of the coating as at 12 to completely cover and surround the neck 10 of the bulb, as disclosed in Figures 1 and 3. llhis coating not only prevents light passage through the neck of the bulb but removes light rays from the axial center of the reflector 5 and eliminates glare at'this point.

The construction described provides a practical and effective method and'means for removing light glare from automobile illuminating head lights, and constitutes a distinct help to the driver of the vehicle by eliminating the necessity of dimming'the lamps when the latter are in use. The lamps produce a strong Well distributed light requisite for all driving purposes but .ane which will not cause discomfort and impaired vision on the part of the approaching drivers.

What is claimed is:

As a new article of manufacture, an incandescent lamp having the glass bulb portion thereof formed to provide transparent and substantially translucent zones, said translu at the lamp base, and the forward portion of said transparent zone being extended to cover an area substantially equal to that of the rear translucent area of the lamp.

In testimonywhereof l aflix my signature. FRANK C. MCELROY. 

